Core A consists of two components: one, the Administrative Core, that will provide overall administrative oversight for the Program; and, two the Biostatistics Core, that will provide help with biostatistical analysis and data management. The primary function of the Administrative Core will be to facilitate scientific interactions between all the investigators of this U19 Application. The following meetings and activities will be organized to foster collaborative studies between the various groups: 1. Emory and the CDC based Investigators will meet monthly at the Emory Vaccine Center to present and discuss their results and to review the progress of the individual projects. 2. An annual meeting will be held in which Investigators from all 5 institutions will participate. 3. An External Scientific Advisory Board (SAB) consisting of five distinguished immunologists and vaccinologists will be set up and members of the SAB will be invited to the Annual Meeting. 4. A yearly symposium on human immunology will be organized to learn about new advances in this area. A weekly Journal Club will be organized in which graduate students/post-doctoral fellows will discuss the latest research in immunology with a special focus on human immunology. In addition to these above activities, the Administrative core will interact closely with the "Education" and "Pilot Project" Components of this U 19 Application and oversee the selection processes for funding the Pilot Projects and for choosing the trainees for the Education component. The primary goal of the Biostatistics Core is to strengthen the research efforts and introduce statistical rigor in the proposed studies. This goal will be accomplished by: 1. Providing statistical services for data analysis, design of experiments, and manuscript preparation. 2. Establishing and maintaining appropriate database, data management and data analysis capabilities and developing software/algorithms. 3. Coordinating with the Clinical Core (Core B) on their databases and maintaining the integrity of the data. 4. Providing one-on-one training in biostatistics methods and data management to investigators, post-doctoral fellows, graduate students and visiting investigators.